The present invention relates to a fabric care composition, which comprises an encapsulated xe2x80x9cfabric or skin beneficiating ingredientxe2x80x9d. More particularly, this invention relates to fabric softening compositions, such as fabric softeners, fabric refreshers, detergents in a form of liquid, powder, gel or a composition applied onto a fabric substrate such as fabric softener sheets and/or wipes.
All above-mentioned compositions comprise three main ingredients: (a) cationic softening compound; (b) non-confined fragrance oil, (c) at least one fabric or skin beneficiating ingredient free of any water-soluble or water-insoluble polymer or nonpolymeric carrier and contained within pressure sensitive microcapsules. This invention provides enhanced delivery of the fabric or skin beneficiating ingredient to the fabric.
The present invention is based on the concept of fragrance, perfume, emollient or other fabric or skin beneficiating ingredient being released xe2x80x9con demandxe2x80x9d, e.g., release at a time of fabric/clothes use and/or wear.
The concept of controlled active release is known in the art, and various methods for achieving this have been developed. One aspect of the controlled release of perfume, for example, is providing slow release of perfume over an extended period of time. This is generally achieved by blending perfume or other fabric or skin beneficiating ingredient with a substance that will, in essence, xe2x80x9ctrapxe2x80x9d the perfume and subsequently release small amounts of perfume over time.
One of the simplest embodiments consists of putting perfume in wax such as described in Canadian Patent No. 1,111,616 to Young, issued November 1981 and in U.S. Pat. No. 6,042,792 to Shefer et al. issued Mar. 28, 2000. Other embodiments encompass the complex technology of microencapsulation, such as in U.S. Pat. No. 4,464,271 to Munteanu et al. issued Aug. 7, 1984 which describes softener compositions containing a non-confined fragrance oil and a fragrance oil entrapped in solid particles.
An example of such microencapsulation technology is embodied in capsules filled with perfume, which are commercially marketed by, e.g., the Reed Pacific Company in Australia or Euracli Company in France. These capsules are adapted to break under friction and provide an instant xe2x80x9cburstxe2x80x9d of the fragrance when the capsules are ruptured. Microcapsules of the aminoplast type are used in the textile industry, and especially in so-called xe2x80x9cintelligent fabricsxe2x80x9d or xe2x80x9csmart textilesxe2x80x9d, such as xe2x80x9cLe carre de soiexe2x80x9d by Hermes or by DIM (women panties with encapsulated emollient). More particularly, Hermes has commercialized luxurious scarves that release the Hermes perfume by friction created by contact with the neck of the consumer. Dim markets panties which release a relaxing agent for the legs. The microcapsules used are deposited on the fabric surface during the fabric finishing operation which is carried out by the textile manufacturer. These microcapsules are generally removed in the course of subsequent domestic washing; typically capsules can withstand about 5 washes before the fabric or skin beneficiating ingredients lose their intended effect.
From the above, it is clear that the preparation of microcapsules is a known art; preparation methods are, for instance, described in detail in a handbook edited by Simon Benita (xe2x80x9cMicroencapsulation; Methods and Industrial Applications, Marcel Dekker, Inc. N.Y., 1996), the contents of which are incorporated herein by reference for the preparation techniques described therein.
The preparation process is also the subject of several patents, such as U.S. Pat. No. 3,516,941 to Matson and U.S. Pat. No. 4,976,961 to Norbury and Chang, the disclosures of which are incorporated herein by reference.
Further reference is made to a number of patent publications, which describe the use of encapsulated fragrance in household applications, and more specifically in detergent compositions and in fabric softener products. For example, U.S. Pat. No. 4,145,184 to Brain et al. describes detergent compositions which contain perfumes in the form of friable microcapsules. Preferred materials for the microcapsule shell walls are the aminoplast polymers comprising the reaction product of urea and aldehyde.
U.S. Pat. No. 5,137,646 to Schmidt et al. issued August 1992, describes the preparation and use of perfumed particles, which are stable in fluid compositions and which are designed to break as the perfumed formulation is used, thereby releasing the perfumed particle. More specifically, this patent describes a fabric softener composition comprising one or more fabric- or fiber-softening or antistatic agents, and perfume particles comprising perfume dispersed in a solid core comprising a water-insoluble polymeric carrier material, such as polymers selected from the group consisting of polyethylene, polyamides, polystyrene, polyisoprenes, polycarbonates, polyesters, polyacrylates, vinyl polymers and polyurethanes. These cores are encapsulated by having a friable coating, a preferred coating being an aminoplast polymer which is the reaction product of an amine selected form the group consisting of urea and melamine and an aldehyde selected from the group consisting of formaldehyde, acetaldehyde and glutaraldehyde.
The perfume/controlled release agent may also be in the form of particles mixed into the laundry composition. According to one known method perfume is combined with a water-soluble polymer to form particles which are then added to a laundry composition, as described in U.S. Pat. No. 4,209,417 to Whyte issued June 1980; U.S. Pat. No. 4,339,356 to Whyte issued July 1982; and U.S. Pat. No. 3,576,760 to Gould et al. issued April 1971; and U.S. Pat. No. 5,154,842 to Walley et al. issued October 1992.
The perfume may also be adsorbed onto a porous carrier material, which may be a polymeric material. See, for example, U.S. Pat. No. 5,137,646 to Schmidt et al.
The present invention provides a stable fabric softening composition comprising:
(a) a cationic softening compound;
(b) a non-confined fragrance oil;
(c) at least one fabric or skin beneficiating ingredient free of any water-insoluble polymer or non-polymeric carrier and which is contained within friable microcapsules comprising an aminoplast polymeric shell, said microcapsules having a diameter of from about 0.1 to about 350 microns, with the proviso that when said fabric beneficiating ingredient is a fragrance oil, said fabric softening composition is prepared by a process comprising the step of adding sequentially or in combination (i) said non-confined fragrance oil of (b); and (ii) the encapsulated fragrance oil of (c) to said cationic softening compound and wherein said non-confined fragrance oil is not mixed with any suspending agent prior to its addition to said cationic softening compound in accordance with said process, whereby the ordinary manipulation of fabric is capable of rupturing the polymeric shell of said microcapsules which are deposited on the fabric surface during treatment with said fabric softening composition to release said fabric or skin beneficiating ingredient.
In a preferred embodiment of the invention the softening composition further includes a nonionic or cationic polymer other than the aminoplast polymer, most preferably a cross-linked cationic polymer to enhance the substantivity and deposition of the fabric or skin beneficiating ingredient on the fabric surface. Particularly preferred cationic polymers for this purpose are derivable from a water soluble cationic ethylenically unsaturated monomer or blend of monomers which is cross-linked by a cross-linking agent comprising polyethylene functions, such as, methylene bisacrylamide. Such cross-linked cationic polymers may also serve to thicken the softening composition. In a less preferred embodiment of the invention non-ionic polymers, such as for example, but not limited to poly(ethylene oxide), non-ionic polyacrylamide, nonionic cellulose ether, modified non-ionic starch polymers, can be used as well.
For purposes of the present invention a xe2x80x9cfabric or skin beneficiating ingredientxe2x80x9d is any substance which improves or modifies the chemical or physical characteristics of the fabric being treated therewith. Examples of such fabric or skin beneficiating ingredients include perfumes or fragrance oils, elasticity improving agents, vitamins, skin conditioners, antibacterial agents, antistatic agents, enzymes, crease proofing agents, UV absorbers, heat proofing agents and brighteners. The most preferred fabric or skin beneficiating ingredient is perfume. Perfume is an especially suitable fabric or skin beneficiating ingredient for use herein since its volatility generally creates special problems when it is used in conventional fabric treatment compositions, such as, fabric softeners.
The terms xe2x80x9cfragrance oilxe2x80x9d or xe2x80x9cperfumexe2x80x9d as used herein refer to any odoriferous material which may be selected according to the desires of the formulator from natural or synthetically produced fragrant substances to impart a desired fragrance. In general, such perfume materials or fragrance oils are characterized by a vapor pressure above atmospheric pressure at ambient temperatures and are ordinarily liquid at ambient temperatures, but may also be solids such as the various camphoraceous perfumes known in the art. A wide variety of chemicals are known for perfumery uses, including blends of various organic compounds such as aldehydes, ketones, esters, and the like. More commonly, naturally-occurring plant and animal oils and exudates comprising complex mixtures of various chemical components are known for use as perfumes, and such materials can be used herein. The perfumes herein can be relatively simple in their composition, or can comprise highly sophisticated, complex mixtures of natural and synthetic chemical components, all chosen to provide a desired fragrance.
The fabric softening compositions described herein may be in the form of a liquid, powder or gel as well as a fabric softener sheet. The liquid form of the composition is generally preferred for domestic automatic washing machine use.